Two-stroke engine



MEA

A. L. R. BERNARD TWO-STROKE ENGINE Filed Jan. 25, 1935 2 Sheets-Sheet l ,Ec/c eased.'

Fh 25, E936.

Feb., 25, ma A, R. BERNARD 2,032,108

TWO-STROKE ENGINE Filed Jan. 25, 1935 2 Sheets-Sheet 2 ifea-affix @MEQ @if Patented Feb. 25, 1936 UNITED STATES PATENT OFFICE TWO STROKE ENGINE Application January 25, 1935, Serial No. 3,528 In Belgium February 9, 1934 10 Claims. (Cl. 12S-Ill) The present invention relates to two stroke engines of the type in which at least a portion of the gases (for instance air) to be fed to the engine passes through the inside of the base of the cylinder before entering the combustion chamber of said cylinder. The invention is more particularly, although not exclusively concerned with engines of this type which include, for each cylinder, an air feed pump the piston of which is not rigid with the cylinder piston, as described in the French Patent No. 688,522 of August, Louis Ren Bernard, led September 7, 1933.

The object of the present invention is to lprovide an engine of the type above referred to in which the gases admitted to the engine cylinder do not contain too high a percentage of oil vapors driven along by said gases as they pass through the engine crank-case.

The essential feature of the present invention consists in providing the engines of the type above mentioned with a partition, provided with a hole for the passage of the connecting rod, adapted to separate from the inside of the crankcase the gases to be fed to the engine cylinder through the inside of the base of said cylinder.

Other features of the present invention will result from the following detailed description of a specific embodiment thereof.

A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawings, given merely by Way of example, and in which:

Fig. l is a vertical sectional View at right angles to the axis of the crank-shaft of the upper part of arvertical internal combustion engine of the two-stroke type made according to the present invention;

Fig. 2 is a sectional view on the line II-II of Fig. 1;

Fig. 3 is a sectional view on the line III- III of Fig. 2.

The two stroke vertical engine shown by way 'of example is so devised that the air to be fed to the engine is compelled to pass through the inside of the base of the engine cylinder I, that is to say under the end face of the driving piston 2 before entering the combustion chamber of said cylinder.

For this purpose use is made of some of the arrangements disclosed by the French patent above referred to in order to obtain an engine in which the whole of the air to be fed to the cylinder is caused to flow through the lower opening of cylinder I.

An engine of this type includes an air feed pump the piston 3 of which is disposed around the base or lower part of the driving cylinder I. This piston 3 is driven through a cinematic gear including a bell crank lever 4 one arm of which is connected, for instance through a connecting rod :'i, with said piston 3, and the other arm of which is connected, through a rod 6, to an axis I carried at a suitable point by the connecting rod 8 interposed between piston 2 and the crankshaft. This gear thus causes the piston 3 of the air pump to be actuated out of phase with the driving piston 2.

The intake of the air pump is controlled by the driving piston itself, the skirt of which has a lower edge 9 and is provided with ports I0. The 15 inow of air to the pump takes place through ports i I provided in the lower part of cylinder I and through the inlet ports of said cylinder, the air admitted into said pump coming from the space below the piston end.

Accor-ding to the prior art, in an engine of this kind, the external air was allowed to enter freely into the crank-case (eventually after having been freed from dust) and to flow therethrough, this air driving along with it a considerable amount 25 of vapors, and even of droplets, of the lubricant present in said crankcase. This resulted, in some cases, in the engine getting rapidly dirty, and especially in the packing rings of the driving piston gumming up after a short time. 30

On the contrary, according to the present invention, there is provided, under the base of the cylinder I, a partition, provided with a hole for the passage of the engine connecting rod, and adapted to separate from the inside of the crank- 35 case, the air to be fed to the engine cylinder through the lower aperture of said cylinder.

For this purpose, there is provided around the lower part of cylinder I a partition I2 limiting a space I3 which surrounds said cylinder except 40 at the place where passes the above mentioned connecting rod 5 through which the piston 3 of the air feed pump is actuated.

On the lateral face of this partition there is provided at least one passage I5 adapted to con- 45 nect said space I3 with a conduit I6 which constitutes the air intake tube. Preferably, an air purifier is provided in said conduit.

A partition il, provided with a passage I8 for the connecting rod 8 of the engine is fixed to the 50 lower edge of partition I2.

Of course, the whole shall be so devised as to reduce as much as possible the passages connecting the inside of the casing with the lower part of the engine cylinder, 55

*l Vfarther describe the operationof the engine ac- For instance, if it is necessary to interrupt partition I2, as shown in the drawings, for affording a passage for the gear that controls piston 3, this partition will be so shaped that its edges eX- tend as near as possible either to the base of the engine cylinder, or to a prolonged part I9 with which said Vpiston 3 is advantageously provided.

Howeve'nfit should be noted that it is not at ali necessary to Aensure full fluidtightnessfbetween Ythe inside of the crank-case and the base of the engine cylinder, the only condition to be obtained,

being that the who-le of the air fed to the engine cyiinder does not pass through theicraniz-caseY where it would drive along with it too large an amount of lubricant.

There is no serious disadvantage in letting a certain portion of the air sucked in to the engineV cylinder come from the engine'lcranls-ase, vThis l portion of the air fed to the engine will always remain very small if the crank-case itself is closed in a fluidtight mannerftnat is to say if noV con- Ytinulous"airstreain is ailowed to flow Ytherethrough.' f

Aperture lris necessarily made of comparatively large sizabut this does not involve any disadvantage. vThis aperture shoulclfbeV so devisedas to prevent lubricant projected from'the crank-case from passing therethrough. For this purpose partition I7 is, for instance, provided with an inwardly extending'e'dge'z of a relatively great height, for instance one half fof the bore of cording to the present invention.

nIn thel specific embodiment labove described, partitionI I2 is iiiiedin'a fluidti'ght manner to the frame 'i4 ofV the engine, but this partition'might befi'xed eitherto Ythe base of the engine Vcylinder or to the'base of the driving pistonif ythe air to be fed'to the engine Ywere to penetrate into the base of the engine cylinderthrough ports suitably provided for this purpose linstead'of owing under the loweredge of said lowler part of thecylin'der.Mv

While the above description discloses whatI is deemedV to be a practical'and efficient embodi- :nent of the' present invention, it'should be well understood that it is not to be limited thereto as there might be changes made'in the arrangement, disposition and form of the parts without departfrm the principleV of the present invention asV co'mi'e-rehended within the scope oftllejaccom panying claims. l Y

What is claimed is:

1. A two-"stroke internal combustion engine which comprises,Y in combination, at least one cylinder, a piston in said cylinder, a crankshaft, a connecting rod between said crankshaft and said piston, a crankcase, a pump having annular cylinder and an'annular piston surrounding saidrstmentione'd cylinder, for feeding (air toY outside'of said crankcase to said a parti,-

, 4; A two-Stroke in Vtion for separating the lower part of'said first mentioned cylinder from said -crankcasa said partition including an annular wall surrounding said lower part of the rst mentioned lcylinder except, on one side thereof wherea passage is left for said transmission means, and extending below the lower edge ofsaid first kmentioned cyl- V inder, and a disceshaped part provided With a hole for the connecting rod, the edge of said hole being bent inwardly. Y

2. A two-stroke internal combustion Vengine comprising, in combination, at least one cylinder, a'piston in said cylinder, acrankshaft, a connectingrod between said crankshaft and said piston, a. crankcase, a pump having a piston for feeding air to the combustion chamber of said cylinder, means foractuating said second piston, means for Vconducting air to said from the interior of that part of said cylinder which is. located on the side of said first piston opposite the combustion chamber, partition'separating the interior of said cylinder from said cranls case, said parti-` tion having na" hole for said connecting rod, and means comprising openings lfor the passagevof fresh air into the interior of. said cylinder.

3. A two-stroke internal combustion eng-ine Y which comprises, in'comhinatinn, at least one cyls inder, a piston in said cylinder, acrankshaft,

connecting rod betweensaid crankshaft andsaid piston, acrankcase, a pump, outside of said cylinder having a piston for feeding-air to. the` com= bustion chamber of, said cylinder, means for acmatins Said Second pistoni Said cylinder having openings in its Wall, said openingsrconnecting the interim Oisad cylinder Wththe inierier of; said Dump, Said. Openings.. beine closed and :ner-led by Saidrst mentonedfpstqnf a, partition for senarating the'interior of said cylinder from` said crankcase, said partitionhaving a, hole 'for said Connecting rod. andmeans comprising openings for the passage of fresh air Vinte the Vinterior of said cylinder. Y n

al combustion. engine feeding air tcthe, Combustion chamber: 0i Said seidcenneeiins rodi. an@ measssornpr' me onen-V Vingsadapted to let fresh air intothe interiQr.-oi

saidcylinder.`

5,'A two-stroke internalV combustion eng-ine Comprising! in Combinatioerat leest; Qrlecvlniier;

a piston in SaidUeylinder, a crankshaft, abonnecting rod between said crankshaft andsaid piston, a crankcase, a pump forfeeding air to th. Combllsiiole'chainbei fff Said rst rlinder.. said pump comprisingean annularfcylinderand an annular piston surrounding said first cylinder, p Y

transmission means Voperative by. said crankshaft for actuatingsaid secondivmentioned kpiston outof phase with respect to themovement of the rst piston, said rst cylinder having openingsfin` itsV wall for connecting its. interior. with the interior of the second cylinder, said openingsbeingvclosed and Opened by- Said first piston. a nartitignfseparating the interior of said first mentioned cylinder from said crankcase, said partition having a hole fo'r said connecting rod,y and means comprising openings for the passage of fresh air into the interior of said first cylinder.

6. A two-stroke internal combustion engine comprising, in combination, at least one cylinder, a piston in said cylinder, a crankshaft, a connecting ro'd between said crankshaft and said piston, a crankcase, a pump for feeding air to the combustion chamber of the first cylinder, said pump comprising an annular cylinder and an annular piston surrounding said first cylinder, transmission means operative by said crankshaft for actuating said second piston out of phase with respect to the movement o'f the rst piston, said rst cylinder having openings in its wall for connecting its interior with the interior of the second cylinder, said openings being closed and opened by said rst piston, a partition separating the lower part of said rst cylinder from said crankcase, said partition including an annular wall surrounding said lower part and a discshaped bottom portion, said bottom portion having a hole for the connecting rod, said annular wall having an aperture on one side thereof for the passage of said transmission means, said annular wall and said bottom portion extending below the lower edge of said rst cylinder so as tol form an air passage, said annular wall having at least one opening for permitting fresh air to pass through said air passage into the interior of said rst cylinder.

'7. A two-stroke internal combustion engine comprising, in combination, at least one cylinder, a piston in said cylinder, a crankshaft, a connecting rod between said crankshaft and said piston, a crankcase, a pump for feeding air to the combustion chamber of the first cylinder, said pump comprising an annular cylinder and an annular piston surrounding said first cylinder, transmission means operative by said crankshaft for actuating said second piston, said rst cylinder having openings in its wall for connecting its interior with the interior of the seco'nd cyl-v inder, said openings being closed and opened by said first piston, means comprising openings for' the passage of fresh air into the interior of said first cylinder, and a partition surrounding the lower part oif said first cylinder so as to separate the inside of the lower part of said rst cylinder from said crankcase, said partition having an aperture on one side thereof for the passage of said transmission means and a hole for said connecting rod.

8. An internal combustion engine according to claim '7 in which the edge of the hole for the connecting rod is bent inwardly toward the cylinder of the engine.

9. A two-stroke internal combustion engine comprising, in combination, at least one cylinder, a piston in said cylinder, a crankshaft, a connecting rod between said crankshaft and said piston, a crankcase, a pump having a piston for feeding air to the combustion chamber of said cylinder, means for actuating said second piston, means for conducting air from the interior of that part of said cylinder which is located on the side of said rst piston opposite the combustion chamber, a partition separating the interior of said cylinder from said crankcase, said partition having a hole for said connecting ro'd, the edge of said hole being bent inwardly toward the cylinder, and means comprising openings for the passage of fresh air into the interior of said cylinder.

10. A two-stroke internal combustion engine comprising, in combination, at least one cylinder, a piston in said cylinder, a crankshaft, a connecting rod between said crankshaft and said piston, a crankcase, a pump having a piston for feeding air to the combustion chamber of said cylinder, means for actuating said second piston `out of phase with respect to the movement of the first piston, means for conveying air to said pump from the interior of that partl of said cylinder Vwhich is located on the side of said rst piston yopposite the combustion chamber, a partition separating the interior of said cylinder from said crankcase and having a hole for said connecting rod, and means comprising openings for the passage of fresh air into the interior of 'said cylinder.

RENE BERNARD, NE BOURNONVILLE. Executri of Auguste Louis Rene' Bernard, De-

ceased. 

